JPH0341662B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling fuel supply to an internal combustion engine equipped with an electronically controlled fuel injection device, and more particularly to a method of increasing the amount of fuel supplied after a fuel supply cutoff (hereinafter referred to as fuel cut) is completed.

A fuel supply control method that uses an electronically controlled fuel injection device and controls the amount of fuel supplied according to the operating state of the engine is to cut off the fuel supply to the engine during deceleration, that is, to perform a fuel cut to improve fuel efficiency and exhaust gas characteristics. After the fuel cut is completed (hereinafter simply referred to as "after the fuel cut"), the amount of fuel supplied is controlled to increase, thereby improving the driving performance. One such control method is a method in which the fuel injection time is lengthened by a predetermined period of time after the fuel cut (1983-
33721 Publication "Electronically Controlled Fuel Injection Device"), or a method in which the amount of fuel after fuel cut is increased according to the fuel cut period (Japanese Patent Laid-Open Publication No.
No. 56-47631 (``Method for controlling fuel supply device'') has been proposed.

However, in each of the above control methods, if the engine speed suddenly decreases due to clutch off after fuel cut, there is a risk of engine stall, and the fuel increase is set to a sufficient amount to avoid such an engine stall condition. Then, since the amount of fuel is increased even when returning to normal, the air-fuel ratio becomes excessively rich, causing problems such as deterioration of exhaust gas characteristics and increase in fuel consumption. Further, the pressure inside the intake pipe when the fuel cut is released from the fuel cut in the state of the power transmission means, that is, during motoring, is higher than the pressure inside the intake pipe during fuel supply operation, that is, during firing.

This difference between motoring and firing occurs for the following reasons.

That is, when fuel is supplied into the cylinder, combustion occurs even during deceleration. When combustion occurs, the flow rate of exhaust gas is larger than when there is no combustion (during fuel cut), and this large amount of compressible fluid (exhaust gas) reduces the residual gas in the cylinder when the exhaust valve is closed, and the cylinder Internal pressure decreases. This causes a reduction in the pressure inside the intake pipe when the intake valve is opened, and the pressure inside the intake pipe during firing becomes lower than the pressure inside the intake pipe when motoring.

For the above reasons, the pressure inside the intake pipe during motoring is higher than the pressure inside the intake pipe during firing, so the amount of fuel required when returning to the normal fuel supply operation state after the fuel cut is increased by the difference in pressure. , disadvantages such as increased fuel consumption, deterioration of exhaust gas characteristics, and decreased driving performance occur.

The present invention has been made in view of the above points, and when returning from a fuel supply cutoff operating state to a fuel supply operating state, when the power transmission means is cut off, the amount of fuel is increased to prevent engine stall and power When the transmission means is connected, the detected value of the intake pipe absolute pressure (hereinafter simply referred to as intake pipe pressure) is corrected to calculate the amount of fuel suitable for the engine operating state after returning to the fuel supply operating state. The aim is to reduce excess fuel consumption and improve fuel efficiency, exhaust gas characteristics, and driving performance.

In order to achieve this object, the present invention includes an electronically controlled fuel injection device, which determines the amount of fuel supplied to the engine according to at least the intake sensory pressure, and injects the engine at a predetermined crank angle immediately after the fuel supply is cut off. In a fuel supply control method for an internal combustion engine, the amount of fuel supplied is controlled to increase by calculating the amount of fuel after the fuel supply cutoff is completed in synchronization with a crank angle signal that is sequentially output for each position. The return to the supply operation state is detected, and from the time of return until a predetermined number of crank angle signals are input, it is determined whether the power transmission means that transmits the torque of the engine to the wheels is disconnected or connected, and the power When the transmission means is cut off, the amount of fuel is increased after the fuel supply cutoff ends, and when the power transmission means is connected, the intake pipe internal pressure is increased to a predetermined value from the time of return until fuel is supplied to all cylinders of the engine. The present invention provides a fuel supply control method for an internal combustion engine that subtracts .

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall configuration diagram of an apparatus for carrying out the control method of the present invention, and reference numeral 1 indicates, for example, a four-cylinder internal combustion engine. It is of the type consisting of a combustion chamber (both not shown). An intake pipe 2 is connected to the engine 1, and the intake pipe 2 includes a main intake pipe communicating with each main combustion chamber and a sub-intake pipe (both not shown) communicating with each sub-combustion chamber. A throttle body 3 is provided in the middle of the intake pipe 2, and a main throttle valve and a sub-throttle valve (both not shown) disposed in a main intake pipe and a sub-intake pipe, respectively, are provided in communication therewith. A throttle valve opening sensor 4 is connected to the main throttle valve to convert the valve opening of the main throttle valve into an electrical signal and send it to an electronic control unit (hereinafter referred to as "ECU") 5.

A fuel injection device 6 is provided in the intake pipe 2 between the engine 1 and the throttle body 3. This fuel injection device 6 consists of a main injector and a sub-injector (both not shown).The main injector is located in the main intake pipe slightly upstream of the intake valve (not shown) for each cylinder, and the sub-injector is located in the sub-intake pipe. These throttle valves are common to each cylinder and are provided slightly downstream of the sub-throttle valve. The fuel injection device 6 is connected to a fuel pump (not shown). Main injector and sub injector are ECU5
The fuel injection valve opening time is controlled by a signal from the ECU 5.

On the other hand, an absolute pressure sensor 8 is provided immediately downstream of the main throttle valve of the throttle body 3 via a pipe 7, and an absolute pressure signal converted into an electrical signal by the absolute pressure sensor 8 is sent to the ECU 5.
sent to. Further, an intake temperature sensor 9 is installed downstream, and this intake temperature sensor 9 also converts the intake air temperature into an electrical signal and sends it to the ECU 5.

Engine water temperature sensor 10 is installed in the main body of engine 1.
The sensor 10 is made of a thermistor or the like, and is inserted into the circumferential wall of the engine cylinder filled with cooling water, and supplies the detected water temperature signal to the ECU 5.

An engine rotation sensor (hereinafter referred to as "Ne sensor") 11 and a cylinder discrimination sensor 12 are installed around the camshaft or crankshaft (not shown) of the engine, and the former Ne sensor 11 receives a TDC signal, that is, 180 degrees of the engine crankshaft. The latter cylinder discrimination sensor 12 outputs one pulse each time a specific cylinder rotates at a predetermined crank angle at a predetermined crank angle position for each rotation, and these pulses are sent to the ECU 5.

A three-way catalyst 14 is disposed in the exhaust pipe 13 of the engine 1 to purify HC, CO, and NOx components in the exhaust gas. On the upstream side of this three-way catalyst 14,
An O ₂ sensor 15 is inserted into the exhaust pipe 13 , and this sensor 15 detects the oxygen concentration in the exhaust gas and supplies the detected value signal to the ECU 5 .

Furthermore, a sensor 16 for detecting atmospheric pressure, an engine starter switch 17, and a battery electrode 18 are connected to the ECU 5.
A detected value signal from the battery electrode 18, a voltage signal from the battery electrode 18, and an on/off state signal from the starter switch 17 are supplied.

Next, details of the fuel control operation of the electronically controlled fuel injection device having the above-described configuration will be explained.

First, FIG. 2 shows the air-fuel ratio control of the present invention, that is,
This is a block diagram showing the overall program configuration of the control contents of the main and sub-injector valve opening times T _OUTM and T _OUTS in the ECU 5. It consists of a main program 1 and a sub-program 2, and the main program 1 is based on the engine speed Ne.
This program performs control in synchronization with the TDC signal and is comprised of a start-up control subroutine 3 and a basic control program 4. On the other hand, subprogram 2 is comprised of an asynchronous control subroutine 5 that is not synchronized with the TDC signal.

The basic calculation formula in the start control subroutine 3 is expressed as T _OUTM = T _iCRM ×K _Ne + (T _V +ΔT _V ) (1) T _OUTS = T _iCRS × K _Ne + T _V (2). Here, T _iCRM and T _iCRS are reference values for the valve opening times of the main and sub-injectors, respectively, and are determined by T _iCRM and T _iCRs tables 6 and 7, respectively. K _Ne is a correction coefficient at the time of starting specified by the engine speed Ne, and is determined by the K _Ne table 8. T _V is a constant for correcting the increase or decrease of the valve opening time according to changes in battery voltage, and is obtained from _TV table 9. _TV is for the sub-injector, while the injector for the main injector is different due to the difference in structure. The amount of ΔT _V is increased according to the operating characteristics of.

Also, the basic calculation formula in basic control program 4 is T _OUTM = (T _iM − T _DEC ) × (K _TA・K _TW・K _AFC・K _PA・K _AS
T・K _WOT・K _O2・K _LS ) +T _ACC × (K _TA・K _TWT・K _AFC ) + (T _V +ΔT _V )…(3) T _OUTS = (T _iS −T _DEC )×(K _TA・K _TW・K _AST・K _P
A ) + T _V …(4) Here, T _iM and T _iS are reference values for the valve opening times of the main and sub-injectors, respectively, and are calculated from the basic Ti map 10, respectively.
This basic Ti map 10 is composed of, for example, a memory, and stores reference values for the fuel supply amount according to the engine speed Ne and the intake pipe internal pressure (absolute pressure P _B ).

T _DEC and T _ACC are constants during deceleration and acceleration, respectively, and are determined by the acceleration and deceleration subroutine 11. Various coefficients such as K _TA , K _TW . . . are calculated by respective tables and subroutines 12. K _TA is the intake air temperature correction coefficient calculated from the table based on the actual intake air temperature, K _TW is the fuel increase coefficient calculated from the table based on the actual engine coolant temperature Tw, and K _AFC is the after-fuel cut coefficient calculated by the subroutine. Fuel increase factor, K _PA
is the atmospheric pressure correction coefficient determined from the table based on the actual atmospheric pressure, K _AST is the post-start fuel increase coefficient determined by the subroutine, and K _WOT is a constant that is the enrichment coefficient of the mixture when the throttle valve is fully opened. , K _O2 is an O ₂ feedback correction coefficient determined by a subroutine according to the actual oxygen concentration in exhaust gas, and K _LS is a constant that is a lean coefficient of the air-fuel mixture during lean/stoichiometric operation. Stoichiometric is an abbreviation for Stoichiometric, which indicates stoichiometric amount, that is, the theoretical air-fuel ratio. Further, T _ACC is a fuel increase constant during acceleration determined by the subroutine, and is determined from a predetermined table.

In contrast, the formula for calculating the valve opening time T _MA of the main injector that is not synchronized with the TDC signal in asynchronous control subroutine 5 is as follows: T _MA = T _iA ×K _TWT・K _AST + ( _TV ΔT _V )...(5) expressed. Here, T _iA is the asynchrony during acceleration,
That is, it is a fuel increase reference value during acceleration control that is not synchronized with the TDC signal, and is determined from the T _iA table 13.
K _TWT is a fuel increase coefficient during synchronous acceleration, after acceleration, and asynchronous acceleration calculated based on the water temperature increase coefficient K _TW obtained from Table 14.

FIG. 3 shows a flowchart of the main program 1 when valve opening time control is performed in synchronization with the TDC signal in the engine ECU 5, and includes an overall input signal processing block A, a basic control block B, and a starting control block C. Consists of. First, in input signal processing program A, when the ignition switch shown in FIG. 1 is turned on, the CPU is initialized (step 1), and the TDC signal is input when the engine is started (step 2). Next, all basic analog values from each sensor are atmospheric pressure P _A , absolute pressure _PB , engine water temperature Tw, atmospheric pressure T _A , battery voltage V, throttle valve opening θth, O ₂ sensor output voltage value V,
and the on/off state of starter switch 17.
Read into the ECU 5 and store the necessary values (Step 3). Then, from the first TDC signal to the next
Count the elapsed time until the TDC signal and calculate the engine speed Ne based on that value.
It is stored in the ECU 5 (Step 4), and based on the calculated value of Ne, it is determined whether the engine speed is less than or equal to the cranking speed (starting speed) (Step 5), and the answer is affirmative (Yes. ), it is sent to the startup control subroutine, and the engine coolant temperature Tw is determined by the T _iCRM table and T _iCRS table.
T _iCRM and T _iCRS are determined based on (step 6), and a correction coefficient K _Ne of Ne is determined based on the K _Ne table (step 7). Then, determine the battery voltage correction constant Tv based on the _TV table (step 8), substitute each value into the previous equations (1) and (2), and calculate T _OUTM ,
Calculate T _OUTS (Step 9).

Also, if the answer in step 5 is negative (No)
If so, it is determined whether or not the engine is in a state that requires a fuel cut (step 10), and if the answer is affirmative (Yes), the values of T _OUTM and T _OUTS are both set to zero and a fuel cut is performed (step 10). Step 11).

On the other hand, if the answer is determined to be negative (No), each correction coefficient K _TA , K _TW , K _AFC , K _PA , K _AST , K _WOT ,
K _O2 , K _LS , K _TWT etc. and correction constants T _DEC , T _ACC ,
Calculate T _V and ΔT _V (step 12). These correction coefficients and constants are determined by subroutines, tables, etc., and ○-○ corresponds to ○-○ in those subroutines.

Next, a predetermined corresponding map is selected according to each data such as the rotational speed Ne, absolute pressure P _B, etc., and T _iM and T _iS are determined based on the map (step 13). Then,
The correction coefficient value obtained in steps 12 and 13 above,
Based on the correction constant value and reference value, the above formulas (3) and (4)
Calculate T _OUTM and T _OUTS (Step 14).
Then, the main and sub-injectors are operated respectively based on the values of T _OUTM and T _OUTS obtained in this way (step 15).

Figure 4 shows the fuel increase coefficient after fuel cut
This is a flowchart of a subroutine for calculating K _AFC .

First, as mentioned above, in the fuel cut determination subroutine, it is determined whether or not the fuel cut is activated (step 1), and if the answer is affirmative (Yes), the number of pulses of the TDC signal supplied and stored in the ECU after the previous fuel cut was completed is determined. η _AFC
is reset to 0 (step 2), and depending on the number of cylinders in the engine, for example, in the case of a 4-cylinder engine, the intake air is reset only while the TDC signal is output four times after returning to the fuel supply operating state (hereinafter simply referred to as "after returning"). In order to correct the pipe internal pressure P _B , the correction number setting value η _MPB is set to 4 (step 3). The set value η _MPB indicates that when the engine speed Ne is the same, the intake pipe pressure P _B during motoring (during fuel cut) is higher than that during firing (during fuel supply operation). During the period from when the engine returns to the motoring state to the firing state, that is,
The amount of fuel supplied to all cylinders should be reduced once each until the absolute pressure sensor is in a state where it can detect the intake pipe pressure P _B at the time of firing after the TDC signal has elapsed four times. Pipe pressure
This is a value that sets the number of corrections to correct P _B. Furthermore, both the injector valve opening times T _OUTM and T _OUTS are set to 0 (step 4), and each main and sub-injector is rendered inactive (step 5).

On the other hand, if the fuel cut condition is not met in step 1, that is, it is determined to be negative (No), the input is made from the point at which the fuel cut ends.
TDC signal pulse η _AFC count value is number of cylinders 4
(Step 6), and if the answer is negative (No), it is determined whether the engine speed Ne at this time is lower than a predetermined low rotation speed N _FCTIL (Step 6). Step 7). This step 7
If it is determined to be negative (No), the process moves to step 18, and if it is determined to be affirmative (Yes), it will be input from the end of the fuel cut.
It is determined whether the number of pulses _ηAFC of the TDC signal has reached a predetermined number, for example eight (step 8). Also,
If the determination in step 6 is affirmative (Yes), that is, if the number of pulses _ηAFC of the TDC signal inputted from the end of the fuel cut exceeds 4, the process immediately proceeds to step 8. If the determination in step 8 is affirmative, the post-fuel cut fuel increase coefficient K _AFC is set to 1 (step 9), and the subroutine is ended without increasing the fuel amount. In addition, if the determination is negative, the set value η _MPB of the number of times of intake pipe pressure correction is set to 0.
In other words, 1 for each cylinder after recovery.
It is determined whether or not the fuel supply for the first time has been completed (step 10).

If the determination in step 10 is affirmative (Yes), it is determined whether a clutch switch (not shown) is off (blocked) or not (step 11). The clutch switch determines whether the clutch is disconnected or connected, and is arranged in conjunction with the clutch, turning on when the clutch is off and outputting a high-level signal. If Yes is determined in step 11, the fuel increase coefficient after fuel cut
From the K _AFC table, a coefficient K _AFC corresponding to the number of pulses η _AFC of the TDC signal input from the end of the fuel cut is read out (step 12). The table of this coefficient K _AFC is set as shown in Fig. 5, for example, and is set immediately after the fuel cut is completed.
TDC signal pulse η The value when _AFC is not input, that is, the initial value K _AFCO is set to the maximum value (>1), and TDC
The signal pulse η decreases sequentially every time _AFC is input,
It becomes 1 when a predetermined number of 8 is reached. The amount of fuel is increased based on the read coefficient K _AFC . In this way, during the period when the number of pulses of the TDC signal is "0" to "3" from the time when the return from the fuel cut is detected, the engine speed is set to the predetermined speed N _FCTIL.
It is determined whether the engine rotation speed is lower than the specified rotation speed or not, and it is also determined whether the power transmission means is cut off or connected, and based on these determinations, the engine rotation speed is
If it is lower than N _FCTIL and it is determined that the power transmission means is in the cutoff state, the coefficient value is
K Execute fuel increase using _AFC . Step 12
The amount increase control is performed after the return detection time, even from the time when the above two conditions are satisfied, as long as it is within the above period.

The reason for doing this is as follows.

That is, in performing the above-mentioned fuel increase control, we have also considered a method of checking the determination result in step 11 or the determination result in step 16 as to whether the transmission is in the neutral position only when the first TDC signal pulse is generated after returning from the fuel cut. However, for example, there are cases where the clutch is disengaged within the TDC period after recovery, and when the clutch is disengaged in this way, fuel is consumed to replenish the inner wall of the intake pipe by the fuel cut, which can lead to engine stall. There is a risk that the engine speed will drop, and this risk becomes even greater especially if the engine speed at that point is low.

Therefore, as mentioned above, the determination as to whether or not step 12 should be executed is made during the predetermined period, and the determination also includes determination regarding the engine speed. This is what I did. Therefore, if you proceed from step 11 to step 12, or if you proceed to step 12 as described below,
When proceeding from Step 16 to Step 12, the flag _ηTFLG is set to 1 (Step 13) and input to indicate that the increase correction is to be performed in Step 12, that is, that the relevant subroutine is being executed.
Add 1 to the pulse η _AFC of the TDC signal (step 14) to count the number of times the subroutine is executed, and set the intake pipe pressure correction number η _MPB.
Subtract 1 from (step 15).

If the determination in step 10 is negative (No), that is, if the routine in step 12 is passed four times and η _MPB = 0 in step 15, and once each fuel supply to all cylinders is completed, the flag η _TFLG is set. Determine whether or not is 1 (step 17),
If the answer is yes, step 12
Proceed to , and in this routine, calculate the coefficient according to the number of pulses of the TDC signal input from the K _AFC table.
Read K _AFC and continue increasing the fuel amount, and if the answer is negative (No), proceed to step 22.

Further, if the determination in step 11 is negative (No), that is, the clutch is on (connected), it is determined whether the neutral switch is off (step 16). A neutral switch (not shown) detects whether or not the transmission is in the neutral position. For example, it is arranged in conjunction with the gear shift lever, and turns on when it is in the neutral position and outputs a high-level signal. do. In addition, it is not limited to detecting the position of the speed change lever, but also the engagement of a predetermined speed change gear,
It may be determined whether or not the signal is neutral by detecting dissociation.

If the determination in Step 7 is negative (No), that is, if the engine rotation number Ne is higher than the predetermined rotation speed N _FCTIL , the amount of fuel supplied after the fuel cut is replaced with an increase in fuel amount by the coefficient K _AFC , and the modified intake pipe In order to execute a subroutine that calculates based on the pressure P _B , the flag η _TFLG is set to 0 (step 18), and the number of corrections set value η _{MPB (} = 4) (step 19). Next, based on the engine speed Ne, the intake pipe pressure difference ΔP _B j (hysteresis width) between motoring and firing is read out from a ΔP _B j table (not shown) (step
20), the intake pipe internal pressure P B is corrected by subtracting the read pressure difference ΔP _B j from the detected value P _B n of the intake pipe internal pressure detected at the time when the TDC signal pulse η _AFC is input, and the corrected intake pipe internal pressure P _B is Pressure P _B (=P _B n-
ΔP _B j) is calculated (Step 21). The detected value
The subscript n of P _B n indicates the number of pulses of the TDC signal input from the time of fuel cut. Based on the corrected intake pipe internal pressure P _B and engine speed Ne, a reference value for the fuel supply amount is read from the basic Ti map 10 shown in FIG. 2. Such correction of the intake pipe internal pressure P _B is executed until the set value η _MPB becomes 0, that is, from the time when the fuel supply operation state is returned to the time when fuel is supplied to all cylinders once. The fuel supply amount is calculated based on this corrected intake pipe internal pressure P _B.

The fuel increase coefficient K _AFC is set to 1 (step 22) by the pulse η _AFC of the TDC signal input immediately after fuel is supplied to all cylinders once each time, so that no further fuel increase control is performed. At the same time, 1 is added to the number of pulses η _AFC of the input TDC signal (step 23).

If step 16 is affirmative (Yes), that is, it is determined that the power transmission means is cut off from the engine, the process proceeds to step 12, and negative (No).
That is, if it is determined that the power transmission means is connected to the engine, the process proceeds to step 18, where the intake pipe pressure P _B is corrected until fuel is supplied to all cylinders once each, as described above. Corrected intake pipe pressure
Determine the fuel supply amount based on P _B.

In addition, if the determination in step 17 is negative (No), that is, when the power transmission means is connected to the engine, one fuel supply to all cylinders is completed during fuel increase control using the coefficient K _AFC . If the engine speed Ne becomes higher than the predetermined speed N _FCTIL (Ne>N _FCTIL ) and the flag _ηTFLG is set from 1 to 0 in step 18,
From now on, it is determined that it is not necessary for fuel increase control and steps are taken.
22 and no increase control is performed.

In this way, excess fuel increase is suppressed by controlling the fuel increase based on the fuel increase coefficient and/or calculating the fuel supply amount based on the corrected intake pipe internal pressure depending on the operating state of the engine after the fuel cut.

As explained above, according to the present invention, the electronically controlled fuel injection device is provided, the amount of fuel supplied to the engine is determined according to at least the pressure inside the intake pipe, and the fuel is injected at each predetermined crank angle position of the engine after the fuel supply is cut off. In a fuel supply control method for an internal combustion engine, the fuel supply amount is controlled to increase by calculating the amount of fuel after the fuel supply cutoff is completed in synchronization with a crank angle signal that is sequentially output. Detects the return to the engine, and determines whether the power transmission means for transmitting the torque of the engine to the wheels is disconnected or connected, from the time of the return until a predetermined number of crank angle signals are input, and the power transmission means is disconnected. When the power transmission means is connected, a predetermined value is subtracted from the intake pipe pressure from the time of return until fuel is supplied to all cylinders of the engine. Therefore, when returning from the fuel supply operating state to the fuel supply operating state, engine stall can be prevented when the power transmission means is cut off, while excess fuel increase can be suppressed when the power transmission means is connected. , it becomes possible to improve fuel efficiency, exhaust gas characteristics, and driving performance.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram showing an embodiment of a fuel supply control device for carrying out the fuel supply control method for an internal combustion engine according to the present invention, and FIG. A block diagram showing the overall program configuration of the valve time control contents, Fig. 3 is a flowchart of the main program shown in Fig. 2, and Fig. 4 is a flowchart of the main program shown in Fig. 2.
FIG. 5 is a flowchart of a subroutine for calculating the fuel increase coefficient after fuel cut of the main program shown in the figure, and FIG. 5 is a diagram showing an example of a table of the fuel increase coefficient after fuel cut. 1... Engine, 2... Intake pipe, 4... Throttle sensor, 5... ECU, 6... Fuel injection device,
8... Absolute pressure sensor, 11... Engine rotation speed sensor.

Claims (1)

[Claims] 1. An electronically controlled fuel injection device, which determines the amount of fuel supplied to the engine according to at least the intake pipe pressure, and outputs the fuel at each predetermined crank angle position of the engine immediately after the fuel supply is cut off. In a fuel supply control method for an internal combustion engine, the fuel supply amount is controlled to increase by calculating an increase in fuel amount after the end of fuel supply cutoff in synchronization with a crank angle signal from a fuel supply cutoff operation state to a fuel supply operation state. and determines whether the power transmission means that transmits the torque of the engine to the wheels is disconnected or connected, from the time of the return until a predetermined number of crank angle signals are input, and whether the power transmission means is disconnected or not. When the power transmission means is connected, the amount of fuel is increased after the fuel supply cutoff is completed, and when the power transmission means is connected, a predetermined value is subtracted from the intake pipe internal pressure from the time of return until fuel is supplied to all cylinders of the engine. A fuel supply control method for an internal combustion engine, characterized in that: 2. The fuel supply control method for an internal combustion engine according to claim 1, wherein the predetermined value is a value corresponding to a difference between an intake pipe internal pressure when the engine is motoring and an intake pipe internal pressure when the engine is firing. 3. The fuel supply control method for an internal combustion engine according to claim 1, wherein when the power transmission means is connected, the fuel amount is not increased after the fuel supply cutoff is completed.